Tensior T8 - Eijkelkamp Agrisearch Equipment

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Important: Only turn of the cap counter-clockwise! Do not store the Tensiometer without the protective plastic bottle since the cup drains fast! The bottle must be filled with some water for storage! 4. Connect the Tensiometer to a readout unit. Carefully insert the T8 into the borehole up to the stop. 24 Do not use any force. The Tensiometer may not be pounded, since cup or pressure sensor can be destroyed. Especially in clayey soils the pressure reading must be monitored as high pressures might build up! The maximum pressure must not exceed 2000 hPa 5. Push the shaft water retaining disk down to cover the soil surface. This prevents water from running into the borehole and down along the shaft. 6. Keep the protective plastic cap on the plug whenever the plug is not connected! 7. Connect the signal cables as described in the chapter "Connecting the T8". 8. The Tensiometer will respond to changes in the soil water tension faster if there is no air inside the system and the soil water conductivity/mobility is high. 9. Write down serial number, position, installation angle and depth.
8 Connecting the T8 The T8 is fitted with an 8-pin plug. The plug can be connected to a Infield 7 handheld measuring device. The Infield 7 displays and stores the soil water tension, the soil temperature and the filling status. With the extension cables offered as accessories the T8 can be connected to a Datalogger or any other data acquisition devices. Please observe the max. supply voltage of 20 VDC. Never connect the signal outputs of the T8 to a supply voltage source! The Tensiometer plug must be covered with the added protective cap anytime the T8 is not connected to an extension cable. 8.1 Single-ended or differential application In general a datalogger with differential inputs should be preferred. This means both the plus signal as well as the minus signal of each sensor are measured. On many dataloggers less channels are required for single-ended measurements, which means only the plus signals are measured and related to the common sensor supply ground. In this case, the voltage drop, depending on the current consumption and the cable resistance, influences the reading and must be compensated: Current consumption: 7 mA; cable resistance: 82 Ω/km ⇒ Voltage drop inside a cable with length 10 m: UError = R x I = 0,82 Ω x 0,007 A = 5,66 mV ⇒ Error for water tension (1 mV equal to 1 hPa): 5,66 mV = 5,66 hPa ⇒ Error for temperature (1°C equal to 20 mV): 5,66 mV = 0,283 °C Therefore, the characteristic lines are lifted for +5,66 hPa resp. +0,283 °C per 10 m cable. The incline is not influenced. For each 10 meters of cable, withdraw 5,66 hPa for pressure (Note: the water tension signal is regarded positive) and 0,283 °C for temperature from the measured signal value to get the correct reading. 25
Page 1: User Manual T8 Tensiometer Version
Page 4 and 5: Table of contents 1 Content of deli
Page 7 and 8: 1 Content of delivery The delivery
Page 9 and 10: installed in the next lower level h
Page 11 and 12: 4.2.2 Temperature sensor A Pt1000 1
Page 13 and 14: 5 Refilling To assure a rapid and r
Page 15 and 16: 7, Before screwing the cup onto the
Page 17 and 18: 3, Close the valve of the vacuum tu
Page 19 and 20: 6.2 Offset correction for non horiz
Page 21 and 22: cup is in a higher position than th
Page 23: 7.8 Documentation For every measuri
Page 27 and 28: 9 Protecting the measuring site 9.1
Page 29 and 30: 10 Additional notes 10.1 Interpreta
Page 31 and 32: 11 Accessories The following equipm
Page 33 and 34: 12 Contact and communication Please

Tensior T8 - Eijkelkamp Agrisearch Equipment

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